Embodiments of the invention relate generally to insulated glass units and, more particularly, to a method for repairing, renewing, or upgrading failing hermetically sealed insulated glass units.
Insulated glass units (also known as double-glazed or double-paned window units) are window units that are commonly used in curtain wall systems of occupied office or residential high-rise buildings or other similar high-rise structures to provide energy efficient and aesthetically pleasing window structures. Insulated glass units are formed generally of a pair of glass panes that are generally parallel to one another and that have a spacer running between them at their peripheries. Spacers, commonly of metal or other suitable components, are adhered by means of a sealant to the glass panes, the sealant desirably forming a gas-tight seal to thus prevent moisture or gas from entering or leaving the space between the panes, with argon or another gas that has a coefficient of thermal conductivity less than that of air commonly filling the space to improve the insulating capacity of the insulated glass unit. Commonly, the between-pane space is filled with gas to a pressure that is approximately atmospheric, although pressure adjustments may be made in connection with the elevation of the geographic locale where the insulated glass unit is to be installed. The sealed gas filled space between the panes thus provides an insulating layer that reduces heat transfer across the unit.
It is recognized that, over a period of time moisture will slowly infiltrate in to the inner cavity or gas/argon may slowly leak from the between-pane space of the insulated glass unit to the atmosphere. This occurs at a rate greater than the permeation of oxygen or nitrogen into the between-pane space, with the result that the pressure in the between-pane space is reduced below atmospheric pressure. The resulting pressure differential causes the panes to cup inwardly, and the panes can eventually touch near their centers, with consequent loss of insulating value. The moisture infiltration into the unit or the leaking of gas/argon from the between-pane space of the insulated glass unit can also cause the window unit to become cloudy from moisture infiltration between the two panes of glass, thereby causing distortion of vision.
When failure of an insulated glass unit occurs, the insulated glass unit necessarily has to be replaced, and this can be extremely expensive in that the failed insulated glass unit must be removed, replaced, and reinstalled on a unit-by-unit basis. In replacing insulated glass units that have failed, existing methods typically rip out the existing window unit and replace it with a new insulated glass unit. The primary disadvantage of this approach, other than cost, is that it opens the occupied building to weather elements and prevents a tenant from occupying the space while this replacement process takes place, and it is recognized that the expense of relocating the tenants, the disruption of operation of businesses, and the loss of rent will be extremely costly. In addition, there are demolition and disposal costs associated with the hundreds or thousands of pounds of glass and other materials of the window units that are being are removed and replaced with new window units. Still further, in the case of multi-level buildings, removal and replacement of the entire window unit is dangerous work, as the removal and replacement must be performed from the outside of the building. These drawbacks, together with the loss of tenancy, makes current techniques for removing and replacing insulated glass units an expensive operation.
It would therefore be desirable to provide a method for repairing/renewing existing insulated glass units, already installed in a building structure, where hermetic seal failure between the two or more panels of glass occurs or is predicted to soon occur. It would further be desirable for such a method to be performed without exposing the interior of the building to outside elements during the repair/renewal, with one panel of the existing unit being retained in the framing while the inside facing panel or panels are removed altogether along with the separating spacer elements.